1. Technical Field
The present invention relates to a mover provided with a plurality of flat plate permanent magnets at outer surfaces of a cornered tubular inner yoke, and to a linear motor formed by a combination of the mover and an armature (stator).
2. Description of Related Art
In a vertical movement device of a drill used in a borer for an electronic circuit board or the like or a vertical movement mechanism in a robot of a pick-and-place type (which picks a component and places the component at a predetermined position), for example, high-speed movement and high-precision positioning are required. Accordingly, such requirements cannot be satisfied by a conventional method for converting an output of a rotation motor into a parallel motion (vertical motion) using a ball screw because the movement speed is low in the conventional method.
Therefore, for such a vertical movement, the use of a linear motor capable of directly deriving a parallel motion output is being promoted. Various types of structures have been proposed for a linear motor in which a rectangular permanent magnet structure provided with a large number of plate-like permanent magnets is used as a mover, an armature having a winding to flow the current is used as a stator, and the mover is arranged in the portion of hole of the stator (see Japanese Patent Application Laid-Open No. 2002-359962 and Japanese Patent Application Laid-Open No. 2008-228545, for example).